Optical micro-electromechanical systems (MEMS) or Spatial Light Modulators (SLMs) are used today in movie and presentation projectors and in televisions to generate images for audiences. Patterns typically appear on large area surfaces such as projection screens or viewing plates. In these applications, visible-wavelength light (400-800 nm) is used. MEMS are also used as switches that direct beams of light from one optical pathway to another. In switching applications, visible-wavelengths of light are typically used, rather than shorter wavelength, ultraviolet light.
The inventors and their colleagues recently have applied SLMs to micro-lithographic processes involved in semiconductor device manufacture. SLMs are being used to generate finer, smaller, and more densely packed imagery. The delineation of the small, densely packed imagery requires use of short wavelengths of light within and below the ultraviolet spectrum. Electrostatic actuation is used to deflect micro mirrors. In order to produce a force, a voltage is generated between two electrodes, one stationary and another that is attached to an actuator for example the movable micro-mirror. An SLM with an array of actuators used in for example a mask writing tool or a chip-manufacturing tool, is loaded with a specific pattern, where actuators are in an addressed state or an unaddressed state when relaying or transmitting a beam of electromagnetic radiation onto a workpiece. This relayed beam of electromagnetic radiation comprises a stamp of a pattern to be printed on said workpiece. This pattern may be a subset of a pattern or a complete pattern to be printed on the mask or the chip respectively.
Accordingly, an opportunity arises to understand the problems of using SLMs with short wavelengths of light, including wavelengths of about 248 nm or less, and to develop methods and devices that adapt SLMs to use with short wavelengths, effectively extending the usefulness and life of MEMS elements.